I got my problem solved. Actually, my image wasn't 8bit. Violet helped me.

When I start Photoshop, I select 8bit, and when I try to save it, 8bit radio button is grayed out. I don't know how can I fix this, maybe I'll use another picture editor, but, I got my main problem solved.

Sorry for disturbing,

if anyone knows how to save 8bit .bmp images in Photoshop, post your ideas.

Thank You in advance,

Pyramid.